The words "syncro" and "4Motion" in the VW brand, as well as the word "quattro" for the Audi brand, have absolutely no bearing on the actual system the car employs. All those words mean is the car is all wheel drive. That's it. So the B3 Passat pictured above, the B2 Passat (Quantum here), and the 3rd generation Transporter (Vanagon here) all were sold in AWD variants and carried the word "syncro" on them yet shared no parts and used three completely different AWD systems.
They changed the moniker from syncro to 4Motion some time in the mid '90s, not exactly sure when because it was during a period where no AWD Volkswagens were being sold here. Audi, however, not only never stopped selling AWD cars here since they came out in the early '80s, but never stopped branding them quattro (lower case 'q', as the word "Quattro" is an actual specific model of the brand). And again, all quattro means is the car is AWD, and there have been various versions over the years, some new versions have come out just within the last few years.
Haldex and Torsen are two brand/types that have been used, but not all AWD VAG products have actually used one or the other.